A path signature perspective of process data feature extraction

Computer-based interactive items have become prevalent in recent educational assessments. In such items, the entire human-computer interactive process is recorded in a log file and is known as the response process. These data are noisy, diverse, and in a nonstandard format. Several feature extraction methods have been developed to overcome the difficulties in process data analysis. However, these methods often focus on the action sequence and ignore the time sequence in response processes. In this paper, we introduce a new feature extraction method that incorporates the information in both the action sequence and the response time sequence. The method is based on the concept of path signature from stochastic analysis. We apply the proposed method to both simulated data and real response process data from PIAAC. A prediction framework is used to show that taking time information into account provides a more comprehensive understanding of respondents' behaviors.